Protective role of antioxidative enzymes and antioxidants against iron-induced oxidative stress in the cyanobacterium Anabaena sphaerica isolated from iron rich paddy field of Chhattisgarh, India

617-630Iron, as an essential element for plants and microorganisms, plays a significant role in photosynthesis, photopigment synthesis, nitrogen fixation, nucleic acid synthesis, etc. However, in iron rich environments, it causes stress by affecting various physiological activities including ROS generation and detoxification machineries. Here, we investigated the protective role of antioxidative enzymes and antioxidants against iron-induced oxidative stress in the cyanobacteria, Anabaena sphaerica from the iron rich regions of Chhattisgarh. We evaluated various morpho-physiological modifications at different concentrations of iron (0, 20, 50, 75 and 100 µM FeCl3). Microscopic and physiological characterization showed highest order of structural deformities, reactive oxygen species (ROS) generation and lipid peroxidation at 100 µM FeCl3 but growth was reduced only by 28%. Possibly, maximum superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities along with highest level of antioxidants (carotenoid, proline, cysteine and non protein thiol) played a major role in protecting the growth. As compared to 20 µM FeCl3 treated cells of A. sphaerica, almost equal growth and no structural alterations at 50 and 75 µM FeCl3 may be correlated with minimum ROS, electrolyte leakage and malondialdehyde (MDA) content along with an activation of efficient ROS detoxification machinery i.e. enhanced level of antioxidative enzymes and antioxidants. Thus, the inherited property of A. sphaerica to grow at iron enriched condition make it more efficient microbe for improvement of the nitrogen status in the soil

Protective role of antioxidative enzymes and antioxidants against iron-induced oxidative stress in the cyanobacterium Anabaena sphaerica isolated from iron rich paddy field of Chhattisgarh, India

Iron, as an essential element for plants and microorganisms, plays a significant role in photosynthesis, photopigment synthesis, nitrogen fixation, nucleic acid synthesis, etc. However, in iron rich environments, it causes stress by affecting various physiological activities including ROS generation and detoxification machineries. Here, we investigated the protective role of antioxidative enzymes and antioxidants against iron-induced oxidative stress in the cyanobacteria, Anabaena sphaerica from the iron rich regions of Chhattisgarh. We evaluated various morpho-physiological modifications at different concentrations of iron (0, 20, 50, 75 and 100 µM FeCl3). Microscopic and physiological characterization showed highest order of structural deformities, reactive oxygen species (ROS) generation and lipid peroxidation at 100 µM FeCl3 but growth was reduced only by 28%. Possibly, maximum superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities along with highest level of antioxidants (carotenoid, proline, cysteine and non protein thiol) played a major role in protecting the growth. As compared to 20 µM FeCl3 treated cells of A. sphaerica, almost equal growth and no structural alterations at 50 and 75 µM FeCl3 may be correlated with minimum ROS, electrolyte leakage and malondialdehyde (MDA) content along with an activation of efficient ROS detoxification machinery i.e. enhanced level of antioxidative enzymes and antioxidants. Thus, the inherited property of A. sphaerica to grow at iron enriched condition make it more efficient microbe for improvement of the nitrogen status in the soil

Deciphering the advanced methodology to investigate the survival of A. sphaerica in iron enriched region of Chhattisgarh

Cyanobacteria are among those tremendous microbial community that adds both aesthetic and ethnic value to the nature. They majorly contribute as a primary producer via photosynthesis due to the presence of various photosynthetic pigments (chlorophyll a, carotenoids, and phycobillisomes) and nitrogen fixation. Apart from this, cyanobacteria also work differently from the league because they bear enormous plasticity in their nature and can survive in the most extreme situations such as saline, thermocline environment, metal and heavy metal prone environment, etc. Iron, one of the second most abundant metal, third most limiting nutrient and fourth most abundant trace element that achieves equal position to that of macro element because of its contribution in all the vital life supporting activities such as photosynthesis, nitrogen fixation and electron transport chain mechanism. The availability and unavailability of iron leads to production of ROS within the cell which is directly linked to an oxidative stress via Haber weiss reaction and Fentons mechanism. So to assess the iron induced stress in cyanobacteria, soils from different locations of Chhattisgarh, have been tested for iron concentration by using Atomic Absorbtion Spectrophotometry (AAS). Then, number of cyanobacterial species was isolated from Turkadih, Bilaspur, and Chhattisgarh having highest iron concentration (140 ppm). They were treated with different concentrations of iron (0, 20, 50, 75, 100, 150 and 200 μM FeCl3). Result suggested that only Anabaena sphaerica a filamentous, heterocystous cyanobacterium could survive up to 100 μM FeCl3 (5 times higher concentration as is used for standard growth medium) and rest of the concentrations were found to be lethal for all the cyanobacterial species. The alterations in morphological, physiological and biochemical attributes were assessed and investigated. Further, proteome analysis (2D- Gel Electrophoresis) of A. sphaerica suggested that some unique proteins need proper investigation via MALDI-TOF. Concisely, it can be said that this part of research creates an interest to investigate at higher and advanced level for the most iron tolerant species isolated from the iron enriched region of Chhattisgarh

Diversity and phylogenetic analysis of heterocystous cyanobacteria using morphological, nitrogen fixation and molecular attributes

586-593Diversity and molecular phylogeny of 22 heterocystous cyanobacteria (Nostocales and Stigonematales), isolated from different paddy fields of Chhattisgarh, India, have been assessed on the basis of microscopic analysis, nitrogen fixing abilities,16S rRNA and nifH genes sequences in conjunction with phylogenetic tools. Variations in morphological attributes along with nitrogen fixing capabilities suggested that these attributes are strains specific. Further, it was supported by the principal component analysis (PCA) plot which showed scattered placement of these heterocystous cyanobacterial strains. The monophyletic origin of the heterocystous clade and the polyphyly of the true branching Stigonematales were observed in the constructed dendrograms based on16S rRNA and the nifH gene sequences. Thus, the use of morphological, physiological (nitrogen fixation) and molecular (16S rRNA and nifH genes sequences) parameters uncovered the better resolution of taxonomic and phylogenetic issues of heterocystous cyanobacteria

Diversity and distribution pattern analysis of cyanobacteria isolated from paddy fields of Chhattisgarh, India

Cyanobacteria have received much attention in soil due to their nitrogen-fixing ability and significant contribution in primary production. The diversity and distribution of unexplored cyanobacteria of Chhattisgarh has been investigated. We attempted to isolate, identify, and characterize the different cyanobacterial strains from different unexplored sites of Chhattisgarh. Twenty-nine strains of cyanobacteria, comprising two unicellular, four colonial, nine unbranched nonheterocystous, 12 unbranched heterocystous, and two pseudobranched cyanobacteria were phenotypically characterized on the basis of microscopic observation, that is, cell width, cell length, average filament length, colonial diameter, and position, shape and dimensions of heterocysts and akinetes. Results suggested that the phenotypic attributes were strain specific. Principle component analysis of heterocystous and nonheterocystous strains proved that environmental factors and physicochemical properties cumulatively decided the structure and distribution of cyanobacteria. These approaches also uncovered cyanobacterial diversity, which help in studying molecular diversity and documentation of unexplored cyanobacteria of Chhattisgarh, India